/*
 * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package org.openjdk.jcstress.util;

public class UnsafeHolder {

    // Unsafe mechanics
    public static final sun.misc.Unsafe UNSAFE;

    static {
        try {
            UNSAFE = getUnsafe();
        } catch (Exception e) {
            throw new Error(e);
        }
    }

    /**
     * Returns a sun.misc.Unsafe.  Suitable for use in a 3rd party package.
     * Replace with a simple call to Unsafe.getUnsafe when integrating
     * into a jdk.
     *
     * @return a sun.misc.Unsafe
     */
    private static sun.misc.Unsafe getUnsafe() {
        IllegalStateException ex = new IllegalStateException("Cannot get Unsafe");

        try {
            return sun.misc.Unsafe.getUnsafe();
        } catch (SecurityException e) {
            // Fall-through
            ex.addSuppressed(e);
        }

        try {
            java.lang.reflect.Field f = sun.misc.Unsafe.class.getDeclaredField("theUnsafe");
            f.setAccessible(true);
            return (sun.misc.Unsafe) f.get(null);
        } catch (IllegalAccessException | NoSuchFieldException e) {
            // Fall-through
            ex.addSuppressed(e);
        }

        throw ex;
    }

}
